In a camera system, for example, as illustrated in FIG. 19, dust 101 may be attached on a light receiving surface 100 (actually on an optical low pass filter since the optical low pass filter is disposed on a front surface of a photosensitive pixel region which is the light receiving surface of a solid-state imaging device) of the solid-state imaging device. The dust may be removed by vibrating the optical low pass filter depending on a model of a camera, but dust having a high adherence property is hardly detached. In this case, a partial region on which the dust is attached is shown as a sensitivity reduction region in a subject image captured by the solid-state imaging device.
Patent Literature 1 discloses a technology that specifies a region where the dust 101 is present and detects a focus using a captured image signal of a region other than the region where the dust is present. Further, Patent Literature 2 discloses a technology that divides a plurality of focus detection regions of the surface of an AF sensor provided separately from the solid-state imaging device into a plurality of blocks, respectively, and nullifies an output of a focus amount detecting unit in a block in which it is determined that the dust is present by a dust presence or absence determination unit. In such a case, when a main subject is reflected in the region where the dust is present, the main subject cannot be focused.
In recent years, burying a phase difference detection pixel on the light receiving surface of the solid-state imaging device started to be distributed. The phase difference detection pixel may be configured, for example, by pupil-dividing two adjacent pixels. For example, as disclosed in Patent Literature 3 below, a light shielding film opening has a smaller area than another general pixel and further, light shielding film openings of two adjacent pixels (pair pixels) are configured to be eccentric in opposite directions.
Even in the solid-state imaging device having the phase difference detection pixel, when the dust is attached on the light receiving surface of the solid-state imaging device, accurate phase difference information cannot be obtained, and as a result, precision of an autofocus (AF) deteriorates. In particular, when a main subject image moves to the dust presence region, an image in which the main subject is focused cannot be captured.